JPH11158269A - Production of polyamide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a polyamide resin having a low melting temp. and an excellent heat resistance by a novel, simple and convenient process. SOLUTION: A mixture comprising 100 pts.wt. polyalkylene terephthalate resin (A) and 10-100 pts.wt. dicarboxylic ester (B) is used as ester compds. 1 mol of the ester compds. (the amt. of ingredient A being based on the repeating units) and 0.5-1.5 mol of a diamine compd. are reacted in a reaction medium comprising at least one solvent selected from among hydrocarbon solvents, halohydrocarbon solvents, ether solvents, acetal solvents, and aprotic protonphobic polar solvents. Thus, at least the divalent OH component of the polyalkylene terephthalate resin is substd. by the diamine compd. to conduct the polyamidation thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyamide resin, and more particularly to a method for advantageously producing a heat-resistant polyamide resin having good melt moldability from a polyester resin as a raw material.

[0002]

BACKGROUND ART Nylon 66, 46, 6T and aramid resins are mass-produced today as heat-resistant polyamide resins having excellent mechanical properties and chemical and physical properties. These nylons 66, 46, 6T and the like are generally produced by reacting an organic dicarboxylic acid and an organic diamine to form a nylon salt and subjecting it to dehydration polycondensation, but the process is complicated. In addition, there is a problem that polycondensation needs to be performed at a high temperature for a long time. In the case of producing an aramid resin, expensive organic carboxylic acid dihalide is required as a raw material, and there are problems such as corrosion of the apparatus due to halogen.

The present inventor has previously described Japanese Patent Application No. 9-69642.
No., a simple and completely different from the conventional polycondensation reaction method,
A new method for obtaining a polyamide resin via a polyester resin without any problem such as corrosion was proposed. According to this method, from polyethylene terephthalate resin (hereinafter abbreviated as PET), for example, polyethylene terephthalamide resin (melting point: 455 ° C.), polyphenylene terephthalamide resin (melting point: 420 ° C.), polyhexamethylene Terephthalamide (melting point: 350 ° C.) can be easily obtained.

[0004] However, since these ultra-high melting point polyamide resins have a high melting point during melt molding, there is a problem in that they are stably melt-molded from the viewpoint of the melt flow temperature and the thermal decomposition temperature of the resin. There was something.

[0005]

The present invention has been made in view of such circumstances, and an object thereof is to solve the above-described problems in the production of polyamide resins, especially heat-resistant polyamide resins. It is to provide a polyamide resin which does not have excellent melt moldability by a simple new process.

[0006]

The melting point of a polymer is related to the rigidity of a molecular chain.
Conventionally, a copolyamide resin is formed by introducing a portion having low rigidity into the molecular chain to obtain a balance between the melting point and the thermal decomposition point (JP-A-59-535).
No. 36, JP-A-59-155426, JP-A-59-161428, JP-A-62-156130
JP, JP-A-5-230204, JP-A-6-2
87300, JP-A-7-82372, JP-A-7-188409, and JP-A-8-48874.

Under these circumstances, the inventor of the present invention has diligently studied a technique for solving the above-mentioned problems in the novel method for producing a polyamide resin, and as a result, the polyalkylene terephthalate resin contains a dicarboxylic acid ester compound. It has been found that when the compound is blended in a specific range and reacted with a diamine compound, a slight decrease in the melting point makes the molding operation extremely easy.

The present invention has been completed on the basis of such findings, and has been developed as an ester compound.
A mixture comprising (A) a polyalkylene terephthalate resin: 100 parts by weight and (B) a dicarboxylic acid ester: 10 to 100 parts by weight is used, and 1 mol thereof (where A component is calculated in a repeating unit), 0.5 to 1.5 mol of the diamine compound is at least one selected from the group consisting of hydrocarbon solvents, halogenated hydrocarbon solvents, ether solvents, acetal solvents, and aprotic phophophobic polar solvents. By reacting in a reaction medium comprising a solvent of at least a divalent OH component in the polyalkylene terephthalate resin with the diamine compound, and amidating the polyalkylene terephthalate resin to produce a polyamide resin. The gist is the law.

That is, according to the method of the present invention, the divalent OH component in the polyalkylene terephthalate resin is reacted with the dialkylene ester and the dialkylene terephthalate resin used as the ester compound. Substitution with the compound causes its polyamidation to occur, and the co-presence of the dicarboxylic acid ester effectively introduces the dicarboxylic acid component of the dicarboxylic acid ester into the molecular chain at an appropriate interval to form copolyamide. This was presumed to have occurred, whereby a reduction in the melting point could be effectively realized, and the moldability could be advantageously improved.

Further, in the present invention, (A) a polyalkylene terephthalate resin:
00 parts by weight and (B) dicarboxylic acid ester: 10 to 10
0 parts by weight, and 1 mol of the mixture (however,
Component A is calculated in repeating units), and 0.5 to 1.5 moles of the diamine compound is used in a hydrocarbon solvent, a halogenated hydrocarbon solvent, an ether solvent, an acetal solvent, and an aprotic solvent. By reacting in a reaction medium comprising at least one solvent selected from the group consisting of proton polar solvents, at least the divalent OH component in the polyalkylene terephthalate resin is replaced with the diamine compound, The gist of the present invention is also a method for producing a polyamide resin characterized by increasing the degree of polymerization by further solid-phase polymerization or melt-polymerization of the obtained reaction product after polyamidization.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

First, the polyalkylene terephthalate resin (A) as a raw material of the ester compound in the present invention is a polyalkylene terephthalate resin (A) of 70 mol% or more and a dicarboxylic acid component comprising terephthalic acid or a terephthalic acid derivative, Obtained by a polycondensation reaction with a divalent OH component comprising an alkylene glycol such as ethylene glycol, propylene glycol, butane-1,3-diol, butane-1,4-diol, and tetramethylene glycol. These dicarboxylic acid components and divalent O
The H component may contain any of the above examples alone or in combination of two or more.

[0013] Examples of such a preferable polyalkylene terephthalate resin used in the present invention include PET, especially, recycled (recovered) PET as waste.

The intrinsic viscosity of the polyalkylene terephthalate resin is at least 0.2 dl / g, preferably at least 0.2 dl / g, measured at a temperature of 30 ° C. using hexafluoroisopropanol (hereinafter abbreviated as HFIP) as a solvent. 0.
Desirably, it is 3 dl / g or more. Get out, 0.2
When the intrinsic viscosity is less than dl / g, the intrinsic viscosity of the polyamide resin obtained by the present invention is low, and even if solid phase polymerization or melt polymerization is performed later, the effect of improving the degree of polymerization is low,
This is because an industrially useful high molecular weight polyamide resin cannot be obtained.

The form of the polyalkylene terephthalate resin used here is not limited, but it is preferably in the form of a powder having an average particle diameter of 2 mm or less, more preferably 1 mm or less. The water content is generally 10%.
It is desirably at most 00 ppm, preferably at most 500 ppm.

On the other hand, in the present invention, the dicarboxylic acid ester (B) used together with the polyalkylene terephthalate resin (A) as an ester compound includes isophthalic acid, phthalic acid, succinic acid, adipic acid, sebacic acid, maleic acid and fumaric acid. It is an ester of an aliphatic or aromatic dicarboxylic acid component such as an acid and an OH component such as methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol and butyl alcohol. Specifically, dimethyl isophthalate, diethyl isophthalate, dibutyl isophthalate, dimethyl phthalate, dimethyl succinate,
Dimethyl adipate, diethyl adipate, dimethyl sebacate, dimethyl maleate, dimethyl fumarate and the like. These may be used alone or in combination of two or more.

In the present invention, the component (B) is subjected to the reaction at a ratio of 10 to 100 parts by weight based on 100 parts by weight of the component (A). If the compounding ratio is less than 10 parts by weight, no effective effect will be exhibited, and if it exceeds 100 parts by weight, the heat resistance of the produced polyamide resin will be significantly reduced. The water content of the component (B) is generally 1,000 ppm or less, preferably 500 ppm.
pm or less.

Further, according to the present invention, the diamine compound which is reacted with the polyalkylene terephthalate resin (A) or the dicarboxylic acid ester (B) as an ester compound includes ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine. Aliphatic diamines such as methylene diamine, octamethylene diamine, dodecamethylene diamine, trimethylene-1,6-hexamethylene diamine; p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, m-toluylenediamine, p- Xylylenediamine, m-xylylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl, 3,
3'-dimethyl-4,4'-diaminobiphenyl,
3,3'-dichloro-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 4,4 '
-Diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, 4,4'-diaminobenzanilide, 3,
3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminoanthraquinone, 3,
3'-dimethoxybenzidine, α, α'-bis (4-aminophenyl) -p-isopropylbenzene, 1,5-
Aromatic diamines such as diaminonaphthalene and 2,6-diaminonaphthalene; 1,3-diaminocyclohexane,
1,4-diaminocyclohexane, 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, piperazine, 2,5-dimethylpiperazine, bis (4-aminocyclohexyl) methane, bis (4-aminocyclohexyl) propane, 4'-diamino-3,3'-dimethyldicyclohexylmethane, α, α'-bis (4-
Aminocyclohexyl) -p-diisopropylbenzene, α, α'-bis (4-aminocyclohexyl) -m
-Alicyclic diamines such as diisopropylbenzene and menthanediamine; and amino-modified polymers such as diaminopolysiloxane. These diamine compounds may be used alone or in combination of two or more.

The amount of the diamine compound used in the present invention is 0.5 to 1.5 mol based on 1 mol of the repeating unit of the polyalkylene terephthalate resin. Especially, it is preferably 0.7 to 1.3 mol, more preferably 0.8 to 1.2 mol. If the amount is less than 0.5 mol, good heat resistance cannot be obtained, and if it exceeds 1.5 mol, the obtained polyamide resin has a low molecular weight or is insoluble when solid-phase polymerization or melt polymerization is performed. This is because it becomes an infusible gel, which causes a problem. The water content is generally 1000 ppm or less, preferably 5 ppm or less.
Desirably, it is not more than 00 ppm.

Further, according to the present invention, the reaction medium in which the polyamide reaction by the reaction between the ester compound comprising the polyalkylene terephthalate resin (A) and the dicarboxylic acid ester compound (B) and the diamine compound proceeds, a specific solvent is used. Is used, and specifically, n
-Butane, i-butane, n-pentane, 2-methylbutane, 2,2-dimethylpropane, n-butylpentane,
3-methylpentane, 2,2-dimethylbutane, n-hexane, 2-methylpentane, 3-butylpentane,
2,3-dimethylbutane, n-heptane, 2-methylhexane, 3-methylhexane, 2,3-dimethylpentane, n-octane, n-nonane, n-decane, isodecane, n-tridecane, benzene, toluene, Xylene,
Ethylbenzene, cumene, n-propylbenzene, n-
Aliphatic, aromatic, aliphatic-aromatic or alicyclic such as butylbenzene, n-octylbenzene, dodecylbenzene (linear, branched), cyclopentane, cyclohexane, decalin, tetralin, methylcyclopentane, methylcyclohexane, etc. Hydrocarbon solvent; 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, p-chlorotoluene, o-dichlorobenzene, m-
Halogenated hydrocarbons thereof, such as chlorobenzene, p-chlorobenzene, 3,4-dichlorotoluene, 1,2,3-trichlorobenzene; diethyl ether, dipropyl ether, dibutyl ether, dihexyl ether, ethyl vinyl ether, butyl vinyl ether; Anisole, phenetole, butylphenyl ether, pentylphenylether, methoxytoluene, benzylethylether, diphenylether, dibenzylether, trioxane, 2-methylfuran, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1 , 2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether,
Examples include ethers such as triethylene glycol diethyl ether and diethyl acetal, and acetal solvents; aprotic phophophobic polar solvents such as acetonitrile, sulfolane, 3-sulfolane, and N-methylpyrrolidone. In addition, even if these solvents are used alone,
Two or more kinds may be used as a mixture. Therefore, the solvent in the present invention includes petroleum ether, petroleum benzine, gasoline, kerosene, and solvent naphtha.
And the water content in such a solvent is 1000 ppm
Or less, preferably 500 ppm or less.

However, aldehydes, ketones, esters, carboxylic acids, or alcoholic solvents commonly used as a solvent, or water or the like react with a diamine compound or hydrolyze a polyester resin. It is not appropriate to use a solvent as the reaction medium in the present invention.

In the method according to the present invention, the necessary amounts of the ester compound and the diamine compound as the reaction raw materials and the solvent are charged to a suitable reaction vessel having a stirring function, and heated.
The intended reaction of replacing the diamine compound with the OH component of the polyalkylene terephthalate resin and the dicarboxylic acid ester used as the ester compound is allowed to proceed,
Furthermore, the dicarboxylic acid structure from the dicarboxylic acid ester is partially introduced into the molecular chain to form a copolyamide. In addition, any of a batch method and a continuous method can be adopted for this reaction.

The reaction temperature in the present invention depends on the reaction pressure, the reaction time, the stirring state, the shape of the ester compound (especially the resin), etc., in addition to the ester compound, diamine compound and solvent used, Preferably it is 120 ° C. or higher. If the temperature is lower than 100 ° C., it takes too much time to produce the copolyamide resin. In addition,
When the reaction temperature is equal to or higher than the boiling point of the solvent (reaction medium) or diamine compound used, the reaction vessel is closed or pressurized.

Further, the reaction time for polyamide conversion in the present invention depends on many factors as well as the above-mentioned reaction temperature, but it is generally 0.2 to 100 hours, preferably 0.5 to 100 hours. 50 hours. If the reaction time is less than 0.2 hours, the production of the polyamide resin is not sufficient,
In addition, if the reaction time exceeds 100 hours, even if the time is extended beyond that, the effect is small.

When the reaction according to the present invention is completed, the polyamide resin as a product existing in the reaction solvent is separated and recovered. This separation and recovery method includes, if the product is dispersed in the reaction solvent in the form of a slurry, as it is, or if it is dissolved, solvent spray drying or adding an appropriate precipitant to precipitate the product. After that, a usual method such as a filtration method and a centrifugal separation method is used. The isolate is
It is dried by a usual drying method such as a hot air drier or a vacuum drier to obtain a target polyamide resin. In addition, the intrinsic viscosity of the polyamide resin thus obtained is usually about 0.3 to 2.5 dl / g.

When it is necessary to further increase the molecular weight of the polyamide resin as a reaction product obtained according to the method of the present invention, it is possible to carry out a so-called solid-phase polymerization method or a melt polymerization method. is there.

Here, the solid-phase polymerization is a method in which a polycondensation reaction is advanced while maintaining a solid state to increase the degree of polymerization. In this case, the polyamide resin as a reaction product is used. Between 50 ° C. above the glass transition temperature and the melting point, preferably 8 ° C. above the glass transition temperature.
From 0 ° C higher to 20 ° C lower than the melting point, 1000
It is realized by performing a heat treatment under reduced pressure of Pa or less, preferably 300 Pa or less or under an inert gas. The heat treatment time at this time varies depending on the temperature, the amount of the reaction product, the shape of the apparatus, and the like.
It is about 0.2 to 20 hours, preferably about 0.5 to 10 hours.

In the melt polymerization method, a polycondensation reaction proceeds under reduced pressure or an inert gas while applying a shearing action to the melt while maintaining the molten state, thereby increasing the degree of polymerization. Method. The melt shearing temperature is not less than the melting point of the formed polyamide resin and not more than the decomposition temperature of the polyamide resin, preferably 20 ° C. or more higher than the melting point of the formed polyamide resin, and 30 degrees higher than the decomposition temperature of the polyamide resin.
° C lower temperature. As the melt polycondensation apparatus under the action of melt shearing, any apparatus capable of kneading a high-viscosity polymer under heating conditions can be used. Specifically, it is a roll, an extruder, a kneader or the like. Among these, a vented extruder and a kneader, which can be easily kneaded at a high temperature, can increase the molecular weight in a short time, and can easily obtain a produced polymer, are preferable. And
As such an extruder, a single-screw or multi-screw extruder is used, and by removing a reaction by-product from a vent under reduced pressure, a high-molecular-weight polyamide resin can be easily formed in a short time. Can be obtained in the form of pellets. The degree of pressure reduction of the vent at that time is 1000 Pa or less, preferably 300 Pa or less. Further, the melting shear time is from 0.2 minutes to 15 minutes, preferably from 0.5 minutes to 10 minutes.

The polyamide resin obtained according to the method of the present invention may contain, if necessary, various compounding agents such as known heat stabilizers, light stabilizers, coloring agents, lubricants, reinforcing agents, and fillers. Are singly or in combination, and a desired polyamide molded article is molded by a usual melt molding method, for example, a method such as compression molding, injection molding, or extrusion molding. Also, such a polyamide resin,
Dissolved in a solvent to form a film by casting,
It can also be used for forming a coating layer.

[0030]

Hereinafter, typical examples of the present invention will be described to clarify the present invention more specifically. However, the present invention imposes no restrictions on the description of such examples. It goes without saying that you don't receive anything. In addition, the present invention, in addition to the following examples, and in addition to the above-described specific description, various changes, modifications, and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that improvements can be made.

Example 1 A commercially available PET bottle was collected, washed, crushed, and sieved to obtain a 10-mesh wire mesh pass product. Then, the obtained recycled PET is
A PET powder sample was prepared by drying at 30 ° C. for 3 hours. The moisture content of the dried product was measured with a moisture meter manufactured by Mitsubishi Chemical Corporation and found to be 100 ppm.

Next, 77 g of the PET powder sample
And a mixture of 33 g of dimethyl isophthalate (Wako Pure Chemical Industries, Ltd., reagent grade 1) together with hexamethylene diamine (Wako Pure Chemical Industries, Ltd., reagent grade 1. Hereafter HMD
1 part by weight) and 10 parts by weight of o-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd., reagent grade 1) are passed through a molecular sieve (manufactured by Wako Pure Chemical Industries, Ltd., 4A) packed column to dehydrate (50 ppm). 733 g of mixed solution (PET
Containing an equimolar amount of 66 g of HMD in the repeating unit of
Each was charged into a 1 L autoclave, pressurized to 0.1 MPa with nitrogen gas, and heated while stirring.
By reacting at 180 ° C. for 10 hours, the divalent OH component in PET and the OH component in dimethyl isophthalate were replaced with HMD. Thereafter, the temperature was lowered to room temperature, and the obtained reaction product was separated by filtration, washed with a large amount of ethanol, filtered again, and then filtered.
Vacuum drying was performed at 0 ° C. for 24 hours to obtain a polyamide product.

On the other hand, for comparison, dimethyl isophthalate was omitted as an ester compound, and only 110 g of a PET powder sample was used to conduct the same experiment as above to obtain a reaction product (comparison).

The melting point of the reaction product according to the present invention obtained as described above was measured using TG / DTA6200 manufactured by Seiko Instruments Inc. as a peak temperature under a temperature rise of 20 ° C./min under nitrogen. 295 ° C. In contrast, the melting point of the reaction product obtained using only the PET powder sample as the ester compound was 308.
° C.

The reaction products of the present invention and comparative examples were injection-molded at a cylinder set temperature of 305 ° C. using a small injection molding machine of 30 tons, respectively. The product melt-flowed and could be molded well, but the reaction product according to Comparative Example 1 did not melt-flow and could not be molded. Therefore, during the injection molding operation of the reaction product according to the comparative example, when the cylinder temperature was gradually increased, flow started at the set temperature: 325 ° C., but foaming occurred frequently, and steady molding could not be performed. Was.

Example 2 Polyamide of PET was produced in the same manner as in Example 1, except that dimethyl isophthalate: 33 g in Example 1 was replaced by dimethyl adipate: 29.6 g.

The obtained reaction product (polyamide) was injection-molded in the same manner as in Example 1. As a result, it was possible to mold the product without any problems such as foaming.

[0038]

As is apparent from the above description, according to the method of the present invention, a polyalkylene terephthalate resin is reacted with a diamine compound in the presence of a dicarboxylic acid ester to form a polyamide, thereby obtaining a melt molding temperature. Can be effectively reduced, and as a result, it is possible to advantageously prevent the occurrence of problems such as a foaming phenomenon during melt molding.

Claims (4)

[Claims] 1. A mixture of (A) a polyalkylene terephthalate resin: 100 parts by weight and (B) a dicarboxylic acid ester: 10 to 100 parts by weight, and 1 mol thereof (where A is 0.5 to 1.5 moles of the diamine compound with respect to a hydrocarbon solvent, a halogenated hydrocarbon solvent, an ether solvent, an acetal solvent and an aprotic phophophobic polar solvent. By reacting in a reaction medium comprising at least one solvent selected from the group consisting of, at least the divalent OH component in the polyalkylene terephthalate resin is replaced with the diamine compound, and the polyamide is formed. A method for producing a polyamide resin, comprising: 2. As the ester compound, a mixture of (A) a polyalkylene terephthalate resin: 100 parts by weight and (B) a dicarboxylic acid ester: 10 to 100 parts by weight is used, and 1 mol thereof (provided that A component is 0.5 to 1.5 moles of the diamine compound with respect to a hydrocarbon solvent, a halogenated hydrocarbon solvent, an ether solvent, an acetal solvent and an aprotic phophophobic polar solvent. By reacting in a reaction medium comprising at least one solvent selected from the group consisting of, at least the divalent OH component in the polyalkylene terephthalate resin is replaced with the diamine compound, and the polyamide is formed. After that, the obtained reaction product is further subjected to solid phase polymerization or melt polymerization to increase the degree of polymerization. Manufacturing method of polyamide resin. 3. The method according to claim 1, wherein the polyalkylene terephthalate resin is a polyethylene terephthalate resin. 4. The method according to claim 3, wherein the polyethylene terephthalate resin is a recovered polyethylene terephthalate resin.